Droughts are extreme climatological events that have major impacts on water resources and agricultural production. Their frequency and intensity may be changing with other aspects of climate change. They can occur from remote influences of ocean temperature anomalies but also from the occurrence of random weather patterns.The mechanisms initiating droughts are strongly seasonally dependent. Remote teleconnections are strongest in the winter season, during which strong low latitude westerly winds can sustain planetary waves. In summer, droughts are largely influenced by random weather evens but also by nearby SST anomalies that can initiate low level circulation systems. This presentation reviews in more detail the occurrences of droughts in the US and China and attribution of their mechanisms.